Jack



A. F.-LANIER.

Patented June 28, 1921.

Amwf'iamw UNITED STATES PATENT OFFICE.

AMOS F. LANIEB, OI WORCESTER. MASSACHUSETTS. ASSIGNOR, BY HESNE ASSTGN- MEN'I'S, TO HI-LO-JAOK COMPANY, A CORPORATION .OF MASSACHUSETTS.

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Specification of Letters Patent. Patented J 1 28, 1921,

Application filed June 4, 1920.' Serial No. 386,520.

To a]? whom it may concern:

Be it known that I, Amos F. LANIEn, a

citizen of the United States, residing at isthat the friction of operation is reducedand also the liability of its failing to function.

The invention also involvesimprovements in details of construction of the parts.

Reference isto be had. to the accompanying drawings, in which Figure 1 is "a side view of a jack constructed in accordance with this invention showing it in its low down position;

Fig. 2 is a similar View showing it expanded, and

Fig. 3 is a horizontal sectional view on the line 3-3 of Fig. 1.

The invention relates to that type of jack in which the principle-of the lazy tongs is employed and comprises a system of links at the meeting ends of the arms to prevent the rocking of the jack and cause the arms on both sides of the jack to work together no matter where the load or strain is located. Jacks of the lazy tongs type have proved very practical in operation, having a wide range of motion and a strong construction and high lifting power.

This invention is shown herein in a form comprising abase 10 of sheet stock. The stock is punched out and turned up to form two vertical walls 11 and 12. One is located near the center. The other near one end. These walls are thus made integral with the base in accordance with this invention. It may be stated here that in previous makes of jacks, one of these side pieces usually has to be assembled after the jack is put together. The base 10 is shown as extending beyond the supporting walls 11 and 12.

These two opposite walls support two cro s shafts 13 n h ch the o e jack arms 14 are pivoted. Each arm extends above and below its pivot to afford places for pivot studs 15 and 16. Each lower stud 15 is connected with the upper stud 16 on the other arm by a link 17, symmetrically located. These links cross each other centrally and as will be seen from a comparison of Figs. 1 and 2, they keep the arms always at the same angle to the horizontal. That is they stabilize the jack because any swinging motion of either arm is communicated in equal degree to the other arm by said links.

These parts are duplicated on the other side and also at the top as will be obvious. The two lower arms 14-. on each side are pinned together by pins 22 or the like, and provided with a connection 23 at the extreme ends with an upper pairof arms 24, which are the same as the arms 14 and connected in the same Way.

Extending across between the ends of the arms is a double threaded right and left hand screw 25 having a square end 26 for the. reception of an extension wrench or crank as is well understood in this art. The two pairs of arms on each side and the opposite ends of the screw are connected together in each case by a nut 23 which has studs '27 projecting from it on which the arms are pivoted.

The stabilizing device at the top: is a duplicate of that at the bottom and the parts are connected upby a load support 30 formed of one piece of dieressed metal and supporting two pivot sha 13.

This constitutes a simplified stabilizing construction that does not involve the complications of making and assembling gears or gear segments nor generate the friction of their rubbing teeth. All parts are in the form of links or arms swinging on pivots and therefore producing a minimum of friction and wear.

There are no laces where stones or dirt can lodge in sue a way as to prevent the operation of the jack as is the case with a pair of meshing gears.

Although I have illustrated and described only one form of the invention I am aware of the fact that changes and modifications can be made therein by those skilled in the are without departing from the scope of the invention as expressed in the claims.

Therefore I do not wish to be limited to all the details of construction shown and described, but what I claim is 1. In a load lifting jack, the combination of a set of arms arranged in the form of a lazy tongs, parallel axes, and crossing links each extending from a point below sald axes to a point above them and pivoted to both arms.

2. In a load lifting jack, the combination of a set of arms arranged in the form of a lazy tongs, two of said arms being pivoted on separated parallel axes in the same horizontal plane, and crossing links each extending from a point below said axes to a point above them and pivoted to one arm at one end and to the other arm at the other end.

form a lazy tongs structure, means extending across the jack for expanding and contracting it, and stabilizing connections consisting of crossing links at top and bottom, located centrally and symmetrically, and pivoted above and below to the ends of the adjacent arms. I

- 4. In a load lifting ack, the combination of four arms pivoted together in pairs to form a lazy tongs structure, means extend-' ing across the jack for expanding and contracting it, and a pressed metal base having two parallel walls cut out and pressed up from it and supporting the ivots on which the lower arms are mounted.

In testimony whereof I have hereunto afiixed my signature.

3. In a load lifting jack, the combination of four arms pivoted together in pairs to AMOS F. LANIER. 

